More chronic total occlusion PCI data expected in 2018

Action Points

Note that this randomized trial demonstrated no benefit for stenting of a concurrent chronic total occlusion during PCI after STEMI.

Be aware that some signal of benefit was seen when that CTO was in the left anterior descending artery.

Additional stenting of a chronic total occlusion (CTO) following percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI) did not confer benefits in left ventricular systolic function, according to the EXPLORE (Evaluating Xience and Left Ventricular Function in Percutaneous Coronary Intervention on Occlusions After ST-Segment Elevation Myocardial Infarction) trial.

Four months after PCI, left ventricular ejection fraction (LVEF) measurements were no different between patients who received extra CTO stenting and those who did not (average 44.1% versus 44.8%, P=0.60), José P.S. Henriques, MD, PhD, of Academic Medical Center in the Netherlands, and colleagues found, in a study published online in the Journal of the American College of Cardiology. Neither patient group had an advantage in mean left ventricular end diastolic volume either (215.6 mL versus 212.8 mL, P=0.70).

On subgroup analysis, however, patients with CTO in the left anterior descending coronary artery had much higher LVEF if they received PCI of that CTO (47.2% versus 40.4% for conservative management, P=0.02).

"Additional CTO PCI within 1 week after primary PCI for STEMI was feasible and safe," the investigators wrote. "The finding that early CTO PCI in the left anterior descending coronary artery subgroup was beneficial warrants further investigation."

While CTO PCI may not be right if the intention is to improve left ventricular systolic function and remodeling in STEMI patients, it may be recommended if the goal is to improve symptoms, Brilakis et al wrote.

"Symptom relief remains the most common reason for CTO PCI referral, and CTO PCI has been shown (in observational studies, but not in randomized controlled studies) to improve angina, dyspnea, refractory arrhythmias, and even depression significantly. With continued exploration, the 'who, why, and how' of CTO PCI will become increasingly clear."

EXPLORE included 304 patients who had acute STEMI and CTO at the time of PCI in 14 centers in Europe and Canada. Patients were randomized to additional PCI of the CTO within a week (150 patients) or conservative treatment without extra PCI (154 patients).

There was a 73% adjudicated rate of procedural success.

"At first glance, the study results appear disappointing because CTO PCI did not improve left ventricular function and dimensions," the editorialists continued. Refusing to rule out the procedure, however, they pointed to the low technical success rate and unknown extent of complete revascularization as limitations to the data.

Henriques and colleagues wrote that another limitation was that the study was not powered to detect differences in hard clinical endpoints such as death, myocardial infarction, and stroke. Generalizability was another issue: the team excluded high-risk patients and included only those who were hemodynamically stable during the first week of primary PCI.

"Randomized controlled trials of CTO PCI are not easy to perform, but are crucial for the further development of the field," Brilakis and colleagues urged, calling EXPLORE "a truly Herculean effort for which the investigators should be congratulated."

Three ongoing randomized trials may elucidate the potential role of CTO PCI (DECISION-CTO, EUROCTO, and SHINE-CTO) -- yet the data are not expected to be available until 2018, Brilakis' group noted.

So what is the role of CTO revascularization in the meantime?

"Despite progressive convergence in procedural strategies and techniques concomitant with the increasing adoption of the hybrid algorithm for CTO crossing, CTO PCI remains a highly specialized and demanding technique that is heavily operator dependent and has a steep and long learning curve," the team wrote, suggesting that the decision to perform the procedure depends on both the operator's and the center's experience.